1. Field of the Invention
This invention is in the field of medicinal chemistry. In particular, the invention relates to the discovery that (R)(−)-2,7,8-triamino-4-(3-bromo-4,5-dimethoxyphenyl)-3-cyano-4H-chromene (1R), substantially free from the corresponding (S)-stereoisomer, is an inducer of apoptosis and is a vascular disrupting agent. The invention also relates to the use of compound 1R, substantially free from the corresponding (S)-stereoisomer, as a therapeutically effective anti-cancer agent, and combination with other anticancer agents, as well as for the treatment of diseases due to overgrowth of vasculature, such as ocular neovascularization.
2. Description of Related Art
Organisms eliminate unwanted cells by a process variously known as regulated cell death, programmed cell death, or apoptosis. Such cell death occurs as a normal aspect of animal development, as well as in tissue homeostasis and aging (Glucksmann, A., Biol. Rev. Cambridge Philos. Soc. 26:59-86 (1951); Glucksmann, A., Archives de Biologie 76:419-437 (1965); Ellis, et al., Dev. 112:591-603 (1991); Vaux, et al., Cell 76:777-779 (1994)). Apoptosis regulates cell number, facilitates morphogenesis, removes harmful or otherwise abnormal cells and eliminates cells that have already performed their function. Additionally, apoptosis occurs in response to various physiological stresses, such as hypoxia or ischemia (WO96/20721).
There are a number of morphological changes shared by cells experiencing regulated cell death, including plasma and nuclear membrane blebbing, cell shrinkage (condensation of nucleoplasm and cytoplasm), organelle relocalization and compaction, chromatin condensation and production of apoptotic bodies (membrane enclosed particles containing intracellular material) (Orrenius, S., J. Internal Medicine 237:529-536 (1995)).
Apoptosis is achieved through an endogenous mechanism of cellular suicide (Wyllie, A. H., in Cell Death in Biology and Pathology, Bowen and Lockshin, eds., Chapman and Hall (1981), pp. 9-34). A cell activates its internally encoded suicide program as a result of either internal or external signals. The suicide program is executed through the activation of a carefully regulated genetic program (Wyllie, et al., Int. Rev. Cyt. 68:251 (1980); Ellis, et al., Ann. Rev. Cell Bio. 7:663 (1991)). Apoptotic cells and bodies are usually recognized and cleared by neighboring cells or macrophages before lysis. Because of this clearance mechanism, inflammation is not induced despite the clearance of great numbers of cells (Orrenius, S., J. Internal Medicine 237:529-536 (1995)).
It has been found that a group of proteases is a key element in apoptosis (see, e.g., Thornberry, Chemistry and Biology 5:R97-R103 (1998); Thornberry, British Med. Bull. 53:478-490 (1996)). Genetic studies in the nematode Caenorhabditis elegans revealed that apoptotic cell death involves at least 14 genes, 2 of which are the pro-apoptotic (death-promoting) ced (for cell death abnormal) genes, ced-3 and ced-4. CED-3 is homologous to interleukin 1 beta-converting enzyme, a cysteine protease, which is now called caspase-1. When these data were ultimately applied to mammals, and upon further extensive investigation, it was found that the mammalian apoptosis system appears to involve a cascade of caspases, or a system that behaves like a cascade of caspases. At present, the caspase family of cysteine proteases comprises 14 different members, and more can be discovered in the future. All known caspases are synthesized as zymogens that require cleavage at an aspartyl residue prior to forming the active enzyme. Thus, caspases are capable of activating other caspases, in the manner of an amplifying cascade.
Apoptosis and caspases are thought to be crucial in the development of cancer (Apoptosis and Cancer Chemotherapy, Hickman and Dive, eds., Humana Press (1999)). There is mounting evidence that cancer cells, while containing caspases, lack parts of the molecular machinery that activates the caspase cascade. This makes the cancer cells lose their capacity to undergo cellular suicide and the cells become immortal—they become cancerous. In the case of the apoptosis process, control points are known to exist that represent points for intervention leading to activation. These control points include the CED-9-BCL-like and CED-3-ICE-like gene family products, which are intrinsic proteins regulating the decision of a cell to survive or die and executing part of the cell death process itself, respectively (see, Schmitt, et al., Biochem. Cell. Biol. 75:301-314 (1997)). BCL-like proteins include BCL-xL and BAX-alpha, which appear to function upstream of caspase activation. BCL-xL appears to prevent activation of the apoptotic protease cascade, whereas BAX-alpha accelerates activation of the apoptotic protease cascade.
It has been shown that chemotherapeutic (anti-cancer) drugs can trigger cancer cells to undergo suicide by activating the dormant caspase cascade. This can be a crucial aspect of the mode of action of most, if not all, known anticancer drugs (Los, et al., Blood 90:3118-3129 (1997); Friesen, et al., Nat. Med. 2:574 (1996)). The mechanism of action of current antineoplastic drugs frequently involves an attack at specific phases of the cell cycle. In brief, the cell cycle refers to the stages through which cells normally progress during their lifetime. Normally, cells exist in a resting phase termed Go. During multiplication, cells progress to a stage in which DNA synthesis occurs, termed S. Later, cell division, or mitosis occurs, in a phase called M. Antineoplastic drugs, such as cytosine arabinoside, hydroxyurea, 6-mercaptopurine, and methotrexate are S phase specific, whereas antineoplastic drugs, such as vincristine, vinblastine, and paclitaxel are M phase specific. Many slow growing tumors, e.g., colon cancers, exist primarily in the Go phase, whereas rapidly proliferating normal tissues, e.g., bone marrow, exist primarily in the S or M phase. Thus, a drug like 6-mercaptopurine can cause bone marrow toxicity while remaining ineffective for a slow growing tumor. Further aspects of the chemotherapy of neoplastic diseases are known to those skilled in the art (see, e.g., Hardman, et al., eds., Goodman and Gilman's The Pharmacological Basis of Therapeutics, Ninth Edition, McGraw-Hill, New York (1996), pp. 1225-1287). Thus, it is clear that the possibility exists for the activation of the caspase cascade, although the exact mechanisms for doing so are not clear at this point. It is equally clear that insufficient activity of the caspase cascade and consequent apoptotic events are implicated in various types of cancer. The development of caspase cascade activators and inducers of apoptosis is a highly desirable goal in the development of therapeutically effective antineoplastic agents. Moreover, since autoimmune disease and certain degenerative diseases also involve the proliferation of abnormal cells, therapeutic treatment for these diseases could also involve the enhancement of the apoptotic process through the administration of appropriate caspase cascade activators and inducers of apoptosis.
It is well known that tumor vasculature is essential for the growth and metastasis of solid tumors. Therefore tumor vasculature is an attractive target for therapy because damaging or blocking a single tumor vessel can kill many tumor cells. There are two major therapeutic approaches targeting tumor vasculature. Antiangiogenic approaches, using antiangiogenic agents such as small molecular inhibitors of VEGF receptors or monoclonal antibody targeting VEGF receptors, are designed to prevent the neovascularization processes in tumors, thus blocking the formation of new blood vessels and tumor growth. Antivascular approaches, using vascular disrupting agents (VDAs, which also were known as vascular targeting agents, VTAs), target the preexisting vessels of tumors, causing vascular shutdown and leading to rapid haemorrhagic necrosis and tumor cell death (Tozer, et al., Nature Review Cancer, 5:423-435 (2005), and Kelland, Current Cancer Therapy Reviews, 1:1-9 (2005)). Vasculature in tumors is known to be proliferating, relatively immature, more permeable and disorganized, in comparison to vasculature in normal tissues. Tumor vascular disrupting agents were designed to exploit these differences between normal and tumor blood vessels and to selectively target tumor vasculature.
Two types of VDAs have been developed. The first types are biological or ligand-directed VDAs which use antibodies, peptides or growth factors to target toxins or pro-coagulants to the tumor endothelium. The second types are small molecule VDAs, and most of them are tubulin-binding agents. Some work through induction of local cytokine production, such as 5,6-dimethylxanthenone-4-acetic acid (DMXAA). VDAs are most effective at killing cells in the poorly perfused hypoxic core of tumors, and leaving a viable rim of well-perfused tumor tissues at the periphery, which can rapidly regrow if not treated. Therefore VDAs as single agents in general have poor anti-tumor effects. However, combination therapies of VDAs with cytotoxic chemotherapy, radiotherapy, and radioimmunotherapy, which target the peripheral tumor cells, have produced excellent responses in many animal tumor models. In general, VDAs are well tolerated and have different side-effect profiles than other types of anticancer therapies. Since VDAs target tumor vasculature, they can kill tumor cells that are resistant to conventional chemotherapy and radiotherapy. In addition, VDAs also should be useful for the treatment of other diseases due to overgrowth of vasculature, such as ocular neovascularization (Numbu, H. et al., Invest Opthalmol. Vis. Sci. 44: 3650-5 (2003)).
Vinca alkaloids and colchicine are known to induce haemorrhagic necrosis of solid tumors. However, these antivascular effects were only observed at doses approaching or exceeding their maximum tolerated doses, therefore they could not be used for therapeutic application. More recently, several tubulin-binding agents interacting at the colchicine-binding site have been found to preferentially target tumor endothelial cells while sparing normal vasculature, and to induce haemorrhagic necrosis of solid tumors at doses that are well tolerated. These compounds include combretastatin A-4 phosphate (CA4P), ZD6126 (N-Acetylcolchinol-O-phosphate) and AVE8062, and have shown high antitumor activity in animal studies, especially in combination with other anticancer agents. Therefore vascular disrupting agents (VDAs) are a promising new class of anti-cancer drugs and several VDAs are currently in clinical trials.
In addition, CA4P was reported recently (Vincent, L. et al., J. Clin. Invest. 115: 2992-3006 (2005)) to induce rapid regression of tumor neovessels through interference with vascular endothelial-cadherin signaling. Specifically, CA4P was found to selectively target endothelial cells, but not smooth muscle cells, and to induce regression of unstable nascent tumor neovessels by rapidly disrupting the molecular engagement of the endothelial cell-specific junctional molecule vascular endothelial-cadherin both in vitro and in vivo. These results provided a mechanism for the antiangiogenic effects of CA4P and for its selectivity against nascent tumor neovessels as opposed to normal stabilized vasculature. Therefore, VDAs can also have antiangiogenic effects.
EP537949 discloses derivatives of 4H-naphthol[1,2-b]pyran as antiproliferatives:
wherein,
each R1 is independently halo, trifluoromethyl, C1-4 alkoxy, hydroxy, nitro, C1-4 alkyl, C1-4 alkylthio, hydroxy-C1-4 alkyl, hydroxy-C1-4 alkoxy, trifluoromethoxy, carboxy, —COOR5 where R5 is an ester group, —CONR6R7 or —NR6R7 where R6 and R7 are each hydrogen or C1-4 alkyl;
R2 is phenyl, naphthyl or heteroaryl selected from thienyl, pyridyl, benzothienyl, quinolinyl, benzofuranyl or benzimidazolyl, wherein said phenyl, naphthyl and heteroaryl groups are optionally substituted, or R2 is furanyl optionally substituted with C1-4 alkyl;
R3 is nitrile, carboxy, —COOR8 where R8 is an ester group, —CONR9R10 where R9 and R10 are each hydrogen or C1-4 alkyl or R11SO2 where R11 is C1-4 alkyl or optionally substituted phenyl;
R4 is —NR12R13, —NHCOR12, —N(COR12)2 or —N═CHOCH2R12 where R12 and R13 are each hydrogen or C1-4 alkyl optionally substituted with carboxy, or R4 is
where X is C2-4 alkylene, or R4 is —NHSO2R14 where R14 is C1-4 alkyl or optionally substituted phenyl; and    n is 0-2.
U.S. Pat. No. 5,281,619 discloses naphthopyrans for therapy of diabetic complications:

wherein,
R1 is C1-4 alkoxy, OH or COOH;
R2 is optionally substituted phenyl;
R3 is nitrile, or R3 is carboxy or —COOR8 when R2 is phenyl substituted with 3-nitro or 3-trifluoromethyl and R8 is an ester group;
R4 is NR12R13, —NHCOR12, —N(COR12)2 or —N═CHOCH2R12, wherein R12 and R13 are each H or C1-4 alkyl; and
n is 0-2.
EP599514 discloses the preparation of pyranoquinoline derivatives as inhibitors of cell proliferation:

wherein R1 is optionally substituted phenyl or optionally substituted heteroaryl selected from thienyl, pyridyl, benzothienyl, quinolinyl, benzofuranyl or benzimidazolyl, or R1 is furanyl optionally substituted with C1-4 alkyl;
R2 is nitrile, carboxy, —CO2R4 wherein R4 is an ester group, —CON(R5)R6 where R5 and R6 are independently H or C1-4 alkyl, or R7SO2 where R7 is C1-4 alkyl or optionally substituted phenyl;
R3 is —NR8R9, —NHCOR8, —N(CO2R8)2, —N═CHOR8 where R8 and R9 are independently H or C1-4 alkyl, or —NHSO2R10 where R10 is C1-4 alkyl or optionally substituted phenyl, or
where X is C2-4 alkylene; and    the ring P represents a pyridine fused to the benzopyran nucleus.
EP618206 discloses the preparation of naphthopyran and pyranoquinoline as immunosuppressants and cell proliferation inhibitors:
wherein,    A-B is CH2CH2 or CH═CH;
each R1 is independently halo, carboxy, trifluoromethyl, hydroxy, C1-4 alkyl, C1-4 alkoxy, C1-4 alkylthio, hydroxy-C1-4alkyl, hydroxy-C1-4 alkoxy, nitrogen-containing heterocyclyl, nitro, trifluoromethoxy, —COOR5 where R5 is an ester group, —COR6, —CONR6R7 or —NR6R7 where R6 and R7 are each hydrogen or C1-4 alkyl;
R2 is phenyl, naphthyl or heteroaryl selected from thienyl, pyridyl, benzothienyl, quinolinyl, benzofuranyl or benzimidazolyl, wherein said phenyl, naphthyl and heteroaryl groups are optionally substituted, or R2 is furanyl optionally substituted with C1-4 alkyl;
R3 is nitrile, carboxy, —COOR8 where R8 is an ester group, —CONR9R10 where R9 and R10 are each hydrogen or C1-4 alkyl, or —SO2R11 where R11 is C1-4 alkyl or optionally substituted phenyl-C1-4 alkyl;
R4 is 1-pyrrolyl, 1-imidazolyl or 1-pyrazolyl, each of which is optionally substituted by one or two C1-4 alkyl, carboxyl, hydroxyl-C1-4 alkyl or —CHO groups, or R4 is 1-(1,2,4-triazolyl), 1-(1,3,4-triazolyl) or 2-(1,2,3-triazolyl), each of which is optionally substituted by a C1-4 alkyl or C1-4 perfluoroalkyl group, or R4 is 1-tetrazolyl optionally substituted by C1-4 alkyl;
X is a pyridine or a benzene ring; and
n is 0-2.
EP619314 discloses the preparation of 4-phenyl-4H-naphtho[2,1-b]pyran derivatives:
wherein,
R1 and R2 are independently halo, trifluoromethyl, C1-C4 alkoxy, hydroxy, nitro, C1-C4 alkyl, C1-C4 alkylthio, hydroxy-C1-C4 alkyl, hydroxy-C1-C4 alkoxy, trifluoromethoxy, carboxy, —COOR8 where R8 is an ester group, —COR9, —CONR9R10 or —NR9R10 where R9 and R10 are each hydrogen or C1-C4 alkyl;
R3 is nitrile, carboxy or —CO2R11 wherein R11 is an ester group;
R4 is —NR12R13, —NR12COR13, —N(COR12)2 or —N═CHOCH2R12 where R12 and R13 are each hydrogen or C1-4 alkyl, or R4 is
where X is C2-C4 alkylene, or R4 is optionally substituted 1-pyrrolyl; and    m and n are each independently 0-2.
The compounds are said to be useful for the treatment of restenosis, immune disease, and diabetic complications.
Smith, et al., (Bioorg. Med. Chem. Lett. 5:2783-2788 (1995)) reported the anti-rheumatic potential of a series of 2,4-di-substituted-4H-naphtho[1,2-b]pyran-3-carbonitriles. They reported that 4-(3-nitrophenyl)-2-(N-succinimido)-4H-naphtho[1,2-b]pyran-3-carbonitrile has proved to be acid stable and still retains biological activity:

Birch, et al., (Diabetes 45:642-650 (1996)) reported that LY290181, an inhibitor of diabetes-induced vascular dysfunction, blocks protein kinase C-stimulated transcriptional activation through inhibition of transcription factor binding to a phorbol response element:

Panda, et al., (J. Biol. Chem. 272: 7681-7687 (1997)) reported the suppression of microtubule dynamics by LY290181, which might be the potential mechanism for its antiproliferative action.
Wood, et al., (Mol. Pharmacol. 52: 437-444 (1997)) reported that LY290181 inhibited mitosis and microtubule function through direct tubulin binding.
PCT published patent application WO9824427 disclosed antimicrotubule compositions and methods for treating or preventing inflammatory diseases. LY290181 was listed as an antimicrotubule agent.
PCT published patent application WO01/34591 disclosed 4H-chromenes and analogs as activators of caspases and inducers of apoptosis:
wherein,    X is O, S or NR6, wherein R6 is hydrogen or optionally substituted alkyl;
Y is CN, COR7, CO2R7 or CONRxRy, wherein R7, Rx and Ry are independently hydrogen, C1-10 alkyl, haloalkyl, aryl, fused aryl, carbocyclic, a heterocyclic group, a heteroaryl group, alkenyl, alkynyl, arylalkyl, arylalkenyl, arylalkynyl, heteroarylalkyl, heteroarylalkenyl, heteroarylalkynyl, carbocycloalkyl, heterocycloalkyl, hydroxyalkyl or aminoalkyl; or Rx and Ry are taken together with the nitrogen to which they are attached to form a heterocycle;
Z is NR8R9, NHCOR8, N(COR8)2, N(COR8)(COR9), N═CHOR8 or N═CHR8, wherein R8 and R9 are independently H, C1-4 alkyl or aryl, or R8 and R9 are combined together with the group attached to them to form a heterocycle;
R5 is hydrogen or C1-10 alkyl;
A is optionally substituted and is aryl, heteroaryl, saturated carbocyclic, partially saturated carbocylic, saturated heterocyclic, partially saturated heterocyclic, arylalkyl or heteroarylalkyl; and
B is an optionally substituted aromatic or heteroaromatic ring.
PCT published patent application WO02/092076 disclosed substituted coumarins and quinolines and analogs as activators of caspases and inducers of apoptosis:
wherein,    the dashed lines cannot both be a double bond at the same time;
X is O, S or NR6, wherein R6 is hydrogen or optionally substituted alkyl or aryl;
Y is CN, COR7, CO2R7 or CONRxRy, wherein R7, Rx and Ry are independently hydrogen, C1-10 alkyl, haloalkyl, aryl, fused aryl, carbocyclic, a heterocyclic group, a heteroaryl group, alkenyl, alkynyl, arylalkyl, arylalkenyl, arylalkynyl, heteroarylalkyl, heteroarylalkenyl, heteroarylalkynyl, carbocycloalkyl, heterocycloalkyl, hydroxyalkyl or aminoalkyl; or Rx and Ry are taken together with the nitrogen to which they are attached to form a heterocycle;
Z is O, S, halo, NR8, or NCOR8, wherein R8 is independently H, C1-4 alkyl or aryl;
A is optionally substituted and is aryl, heteroaryl, saturated carbocyclic, partially saturated carbocyclic, saturated heterocyclic, partially saturated heterocyclic, arylalkyl or heteroarylalkyl; and
B is optionally substituted and is an aryl, heteroaryl, saturated carbocyclic, partially saturated carbocyclic, saturated heterocyclic, or partially saturated heterocyclic ring.
PCT published patent application WO02/092083 disclosed 7,8-fused 4H-chromene and analogs as activators of caspases and inducers of apoptosis:
wherein,
X is O, S or NR6, wherein R6 is hydrogen or optionally substituted alkyl;
Y is CN, COR7, CO2R7 or CONRxRy, wherein R7, Rx and Ry are independently hydrogen, C1-10 alkyl, haloalkyl, aryl, fused aryl, carbocyclic, a heterocyclic group, a heteroaryl group, alkenyl, alkynyl, arylalkyl, arylalkenyl, arylalkynyl, heteroarylalkyl, heteroarylalkenyl, heteroarylalkynyl, carbocycloalkyl, heterocycloalkyl, hydroxyalkyl or aminoalkyl; or Rx and Ry are taken together with the nitrogen to which they are attached to form a heterocycle;
Z is NR8R9, NHCOR8, N(COR8)2, N(COR8)(COR9), N═CHOR8 or N═CHR8, wherein R8 and R9 are independently H, C1-4 alkyl or aryl, or R8 and R9 are combined together with the group attached to them to form a heterocycle;
R1-R2 are independently hydrogen, halo, haloalkyl, aryl, fused aryl, carbocyclic, a heterocyclic group, a heteroaryl group, C1-10 alkyl, alkenyl, alkynyl, arylalkyl, arylalkenyl, arylalkynyl, heteroarylalkyl, heteroarylalkenyl, heteroarylalkynyl, carbocycloalkyl, heterocycloalkyl, hydroxyalkyl, aminoalkyl, carboxyalkyl, nitro, amino, cyano, acylamido, hydroxy, thiol, acyloxy, azido, alkoxy, carboxy, methylenedioxy, carbonylamido or alkylthiol;
R5 is hydrogen or C1-10 alkyl;
A is optionally substituted and is aryl, heteroaryl, saturated carbocyclic, partially saturated carbocylic, saturated heterocyclic, partially saturated heterocyclic, arylalkyl or heteroarylalkyl; and
B is optionally substituted and is a fused thiazole, oxazole, 2-imino-imidazole, 2,1,3-thiadiazo-2-one, thiazol-2-one, oxazol-2-one, imidazol-2-thione, thiazol-2-thione, oxazol-2-thione, imidazoline, oxazoline, thiazoline, triazole, oxazine, oxazine-2,3-dione, or piperazine ring.
PCT published patent application WO02/092594 disclosed substituted 4H-chromenes and analogs as activators of caspases and inducers of apoptosis:
wherein,
R1R4 are independently hydrogen, halo, haloalkyl, aryl, fused aryl, carbocyclic, a heterocyclic group, a heteroaryl group, C1-10 alkyl, alkenyl, alkynyl, arylalkyl, arylalkenyl, arylalkynyl, heteroarylalkyl, heteroarylalkenyl, heteroarylalkynyl, carbocycloalkyl, heterocycloalkyl, hydroxyalkyl, aminoalkyl, carboxyalkyl, nitro, amino, cyano, acylamido, hydroxy, thiol, acyloxy, azido, alkoxy, carboxy, methylenedioxy, carbonylamido or alkylthiol; or R1 and R2, or R2 and R3, or R3 and R4, taken together with the atoms to which they are attached form an aryl, heteroaryl, partially saturated carbocyclic or partially saturated heterocyclic group, wherein said group is optionally substituted;
R5 is hydrogen or C1-10 alkyl;
A is optionally substituted and is aryl, heteroaryl, saturated carbocyclic, partially saturated carbocylic, saturated heterocyclic, partially saturated heterocyclic or arylalkyl;
Y is CN, COR7, CO2R7 or CONRxRy, wherein R7, Rx and Ry are independently hydrogen, C1-10 alkyl, haloalkyl, aryl, fused aryl, carbocyclic, a heterocyclic group, a heteroaryl group, alkenyl, alkynyl, arylalkyl, arylalkenyl, arylalkynyl, heteroarylalkyl, heteroarylalkenyl, heteroarylalkynyl, carbocycloalkyl, heterocycloalkyl, hydroxyalkyl or aminoalkyl; or Rx and Ry are taken together with the nitrogen to which they are attached to form a heterocycle; and
Z is NR8R9, NHCOR8, N(COR8)2, N(COR8)(COR9), N═CHOR8 or N═CHR8, wherein R8 and R9 are independently H, C1-4 alkyl or aryl, or R8 and R9 are combined together with the group attached to them to form a heterocycle.
PCT published patent application WO03/097806 disclosed substituted 4-aryl-4H-pyrrolo[2,3-h]chromenes and analogs as activators of caspases and inducers of apoptosis:
wherein,
R1 is selected from the group consisting of alkyl, cycloalkyl, cycloalkylalkyl, hydroxyalkyl, haloalkyl, alkoxyalkyl, aminoalkyl and oxiranylalkyl;
R3 and R4 are independently hydrogen, halo, haloalkyl, aryl, fused aryl, carbocyclic, a heterocyclic group, a heteroaryl group, C1-10 alkyl, alkenyl, alkynyl, arylalkyl, arylalkenyl, arylalkynyl, heteroarylalkyl, heteroarylalkenyl, heteroarylalkynyl, carbocycloalkyl, heterocycloalkyl, hydroxyalkyl, aminoalkyl, carboxyalkyl, nitro, amino, cyano, acylamido, hydroxy, thiol, acyloxy, azido, alkoxy, carboxy, methylenedioxy, carbonylamido or alkylthiol;
R5 is hydrogen or C1-10 alkyl;
A is optionally substituted and is aryl, heteroaryl, saturated carbocyclic, partially saturated carbocyclic, saturated heterocyclic, partially saturated heterocyclic or arylalkyl;
D is optionally substituted and is a heteroaromatic, partially saturated heterocyclic or saturated heterocyclic fused ring, wherein said fused ring has 5 or 6 ring atoms, wherein one or two of said ring atoms are nitrogen atoms and the others of said ring atoms are carbon atoms;
Y is CN, COR19, CO2R19 or CONR20R21, wherein R19, R20 and R21 are independently hydrogen, C1-10 alkyl, haloalkyl, aryl, fused aryl, carbocyclic, a heterocyclic group, a heteroaryl group, alkenyl, alkynyl, arylalkyl, arylalkenyl, arylalkynyl, heteroarylalkyl, heteroarylalkenyl, heteroarylalkynyl, carbocycloalkyl, heterocycloalkyl, hydroxyalkyl or aminoalkyl; or
R20 and R21 are taken together with the nitrogen to form a heterocycle; and
Z is NR22R23, NHCOR22N(COR23)2, N(COR22)(COR23), N═CHOR19 or N═CHR19 wherein R22 and R23 are independently H, C1-4 alkyl or aryl, or R22 and R23 are combined together with the group attached to them to form a heterocycle.
Kasibhatla, et al., (Mol. Cancer Ther. 3:1365-74 (2004)) reported a novel series of 2-amino-4-(3-bromo-4,5-dimethoxy-phenyl)-3-cyano-4H-chromenes as apoptosis-inducing agents discovered using a cell-based apoptosis screening assay. Several analogues from this series including MX-58151, were found to be tubulin destabilizers with binding site at or close to the colchicine binding site. These compounds displayed high selectivity against proliferating versus resting cells, and were shown to disrupt preformed endothelial cell capillary tubules in vitro, suggesting that they should work as tumor vasculature targeting agents.
Gourdean, et al., (Mol. Cancer. Ther. 3:1375-84 (2004)) reported the evaluation of a group of 2-amino-4-(3-bromo-4,5-dimethoxy-phenyl)-3-cyano-4H-chromenes to disrupt tumor vasculature and to induce tumor necrosis in vivo. One of the compounds, named MX-116407, was found to be highly active and produced tumor regressions in all testing animals in a human lung tumor xenograft (Calu-6) model. Moreover, MX-116407 significantly enhanced the antitumor activity of cisplatin, resulting in 40% tumor-free animals.
Kemnitzer, et al., (J. Med. Chem. 47:6299-310 (2004)) reported the discovery of 4-aryl-4H-chromenes as a new series of apoptosis inducers and the structure-activity relationships (SAR) of the 4-aryl group. 2-Amino-4-(3-bromo-4,5-dimethoxyphenyl)-3-cyano-7-(dimethylamino)-4H-chromene (MX-58151) and 2-amino-3-cyano-7-(dimethylamino)-4-(5-methyl-3-pyridyl)-4H-chromene were identified as the lead compounds from these studies.

Kemnitzer, et al., (Bioorg. Med. Chem. Lett. 15:4745-51 (2005)) reported the exploration of the SAR of 4-aryl-4H-chromenes via modifications at the 7- and 5-, 6-, 8-positions. Several 7-substituted and 7,8-di-substituted compounds, such as 2,7-diamino-4-(3-bromo-4,5-dimethoxyphenyl)-3-cyano-4H-chromene and 2,7,8-triamino-4-(3-bromo-4,5-dimethoxyphenyl)-3-cyano-4H-chromene were found to have similar potencies as MX-58151, both as caspase activators and inhibitors of cell proliferation.

Kemnitzer, et al., (J. Med. Chem. 50:2858-2864 (2007)) reported the exploration of the SAR of 4-aryl-4H-chromenes with fused rings at the 7,8-positions. Several of these compounds, such as 2-amino-4-(3-bromo-4,5-dimethoxyphenyl)-3-cyano-4,7-dihydropyrano[2,3-e]indole and 2-amino-4-(3-bromo-4,5-dimethoxyphenyl)-3-cyano-4,9-dihydropyrano[3,2-g]indole were found to be highly active both as caspase activators and inhibitors of cell proliferation.
